Osmosis! The Diffusion of water!

Osmosis- the diffusion of water through a selectively permeable membrane

Endocytosis- the process of taking material into the cell by means of infoldings, or pockets, of the cell membrane

Active transport- when cells move materials in the opposite direction against a concentration difference

Facilitated diffusion- molecules that cannot diffuse across the cell membrane's lipid bilayer on their own move through protein channels instead.